Lieutenant Colonel

In the US military (excepting the Navy), the fifth officer rank is lieutenantcolonel. The Navy equivalent is called a commander, except when at the helm, at which point he is referred to as "Captain." Likewise, in the other three services, a lieutenant colonel is usually called simply "Colonel" or "Colonellast name," unless it is unclear which officer is being named. Since O-5 is usually the grade at which an officer receives his or her first command, the personnel serving under this command refer to him or her as "The Colonel" to distinguish him or her from any other equally-ranked (but non-commanding) personnel in the unit.